Conventionally, a contacting device comprises a plurality of contact strips, and a mounting block for mounting the contact strips. In order to perform testing on an electronic component, the component being tested is positioned onto the contact strips so that electrical leads of the component make electrical contact with the contact strips. Upon electrical contact being made, the electronic component is then generally driven further in the direction of the contact strips to bend the contact strips and to ensure that there is good contact between the electrical leads of the component and the contact strips.
This is because whether the electrical contact is good enough to ensure testing reliability is determined by the contact resistance between the electrical leads and the contact strips. For the purpose of ensuring that there is good contact, the contact pressure between the electrical leads on the electronic component and the contact strips has to be greater than a certain predetermined level, which level usually depends on the materials from which the electrical leads and contact strips are made of.
In turn, in order to create sufficient contact pressure, the electronic component is driven towards the contact strips for a certain distance so as to bend the contact strips. The bending force on the flexible contact strips will provide a reaction force on the electrical leads of the component, thereby creating the required contact pressure to ensure good contact.
FIG. 1 is an isometric view of contact strips 104 mounted on a mounting block 102 in a prior art test contactor 100. The contact strips 104 comprise elongated strips of electrically-conductive material which are centrally attached and mounted to a mounting block 102. When the contact strips 104 are not contacted with electrical leads of an electronic component, they are generally arranged horizontally and flat.
During testing of an electronic component, electrical leads on the electronic component are made to press on the ends of the contact strips 104. After contact has been made between the contact strips 104 and electrical leads of the electronic component, the electronic component is driven further downwards so as to bend the contact strips 104 from their horizontal positions and to stress them. The required contact pressure is formed to ensure good contact once the flexible contact strips 104 have been bent by a certain predetermined distance.
A disadvantage of adopting this approach is that, in addition to positioning the electronic component next to the contact strips during testing, the electronic component has to be driven by a certain distance towards the contact strips at every testing cycle until the contact resistance between the electrical leads of the component and the contact strips is low enough to create good contact therebetween. The additional time taken to drive the electronic component further by a predetermined distance during the electrical test of every component significantly slows down the testing cycle.
U.S. Pat. No. 5,743,749 describes an electronic component connector in which terminals are formed on a measurement circuit board. Support members are provided on the measurement circuit board to correspond to the terminals, and the support members have free end portions with contacts to come into contact with the electrical lead terminals of electronic components for testing. These contacts are formed of separate members from the support members in order to increase the freedom in selecting the material of the contact which need not have elasticity. Thus, the performance of the electronic component connector can be improved by the selection of appropriate materials to reduce interference during high frequency testing. However, this approach still requires a relatively large travel stroke in order to create enough contact force to ensure good contact and to reduce contact resistance during electrical testing.